The voltammetric behavior of the underpotential deposition (UPD) of copper in sulfuric acid solutions on a series of stepped surfaces (n = 3.5, 5, 6.5, 9, 19, 40, infinity for n(111)x(100)) has been examined in detail. The results are compared with hydrogen adsorption-desorption voltammograms. The potentials of anodic peaks and cathodic peaks coincide for very low potential scan rates except in one case where the anodic peak potential is about 10 mV positive of the cathodic peak potential on the wide terrace of (111) at 0.05 mV s(-1). Copper UPD in sulfuric acid solution is a very slow process. It is shown that step structures profoundly affect the behavior of copper UPD.